Rose and Lynn is by far the most common shipping I've seen so far, so you're not alone. I am not sure how much I actually want any love in the show (I caught parts of Over The Garden Wall chapter 9, and the little remaining sympathy I had with Wart vanished after that episode), but as Rose is in toy canon dreaming about finding love, I have played on a small-scale with Rose x Fabian, and on an even smaller scale Bella x Cedric.
Zack and Fabian has had some close moments, even if by tumbling. It could get interesting to know what Fabian is even doing at the Academy, but if he by profession has a reason to go along with Zack (or to know Zack better), that would fuel that shipping like a lit torch on a Texas oil field.
I have problems seeing reasonable reasons to ship Fabian x Cedric, or Fabian x Princess Sparkle, to name some possible obstacles. Also, welcome to the Fillychan site, Greyfeather!